Space telegraphy.



' L. DE FOREST.

. sncf. fm. APPLICATION HL GR A? HY an un. s. 1902- UBHBBTS-SBBET 3.

N0 MODEL.

' No; 730,246. `1 ATENTBD JUNE 9, 190s..V

L. DE FOREST. SPAGE TBLEGRA'PHY.

APPLICATION FILED MAB.. 8, 1902. N0 MODEL.

` 5 SHEETS-SHEET, 2.

v INV'ENTUQ v f Wm/f5 N'. 730,246.1. PATENTED JUNE 9,'1-903r P LDPPoREsT.

` SPACE TPLEGRAPHY; APPLICATION FILED PAP; e, labs. E v

No 1101131.. s SHEETS-snm 5.

UNITED p STATES LEE DE FOREST, 0E NEW HAVEN,

GREATER NEW YORK` SECURITY COMPANY, OF NEW YORK, N. Y., A CORPORATIONOI" NEW YORK.

,S PAC E-TE,L;EG RAPHY.

srEcIFIcA'rIoN foi-ming partei' Letsratem No. 730,246, 'dated June l9,1903.

Application liled March 8, 19021.

-transmission of the electrical impulses and which are ordinarilyreferred to as space or wireless telegraphy.

My invention comprises certain novel fleatures, which will be hereindescribed, and particularly pointed out in the claims.

In the drawings accompanying herewith I` have shown and inthespecification have described numerous forms of apparatus in illustrationof the manner of applying my invention to use and of adapting it todifferent circumstances and requirements. I am aware, however, that itmaybe embodied in other forms, and do not, therefore, wish to be under-Ystood as limiting myself to the forms herein shown, but seek to claim myinvention in any form in which it may be embodied. The scope of myinvention is to be determined bya reference to the accompanyingdescription and! particularly to the claims attached thereto. f

The accompanying specification is a den scription of my invention asembodied in the figures of drawings given.

Figure l shows an apparatus embodying my invention used as a sender.vFigyZ showsdiagrammatically a simple form of apparatus containing myinvention employed Ias a r' 'ceiveiz -Figs 3 to 7, inclusive,show-modiiied forms, which by the use of either a responder or anenergizing device may be used either as a sender or as a receiver.Figs.` Sto Il, inclusive, show my invention in various modificationsemployed as senders. Figs. l2 to 23, inclusive, show forms of myinvention employed as receivers. Figs. 2i, 25, and 26 show otherarrangements of parts employed in my invention.

iVhile I have shown and described some arrangements employed asreceivers and others l fall in amplitude to nothing.

Patented rune 9, 190s.

PATENT OFFICE.

CONNECTICUT, AssiGNoR To THE Serial No. 97,239. (No model) arrangementsshown in either capacity by substituting either a responder or anenergiz-y ing apparatus for whichever of theseis shown. In systems ofspace or wireless telegraphy now being employed a failure to attain theefficiency or power desired is largely due to the 6o fact that theelectrical waves emanating from the sending device are rapidly damped orde'- creased in intensity or amplitude. In other Words, while themaximum intensity or amplitude of th e Waves may be satisfactory their 65 persistence is unsatisfactory, as they rapidly K In consequence ofthis their energizing action uponthe receiving-antenna being repeatedbut a few times does not have the cumulative energizingy ef- 7o fectthat a much weaker impulse would have lif repeated a greater number oftimes. The leffect is comparable to the effect produced upon a vibrantbody, as a pianowire,by its note being sounded loudly for a very shortnected each with a terminal of any form of apparatus producingelectrical oscillations of high frequency the charges in said Wires atany point of their length lare of exactly equal intensity and ofopposite phase'. The currents flowing in these two wires ,are also atlcorresponding points equal inkv amount and flow in opposite directions.If these` wires are the equivalent of onequarte'r or any multiplethereof of the wave lengtlrofthe electrical oscillations transmittedthereto, very efficient reflection occurs at the ends of these wires,with the-result that stationary or standn ing waves are set up, causedby the incident and reiiected oscillations. The-system then divides upinto quarter'or half wavelengths roo. l

with nodes and loops symmetrically situated on each wire. At the nodesof these electrostatic stationary waves a conducting-body, as a wirebridge, may be placed across both wires without seriously interferingwith the action beyond.V At a distance of one-quarter wave length fromsaid nodes loops are formed, at which points the maximum possiblediflerence of potential between the two parallel wires exist. Such asystem of parallel conductors is known in the art as the Leclier systemof wires. The phenomena involved in this system have been worked outtheoretically, notably by Lord Rayleigh, Drude, Heaviside, and others,and have been set forth by these and other people, as in the followinginstances: By E. Lecher, in VVz'cflcmanns Annalen, No. 4l, page 850;Barton and Bryan, Phil. lll-(Lg. August, 1897; E. Marx, l/VlcalenmnnsAnnalen, No. ll, 1808; Lord Rayleigh, Phil. lifag. No. 43, 1897; E.Lecher, lVzccl@mami/3 Annalen, No. 42; Heaviside, London Elecifrlcl'tm,April 1897; Bjerknes, 'l/Vedcmmms Annalen, No. 55, page 121. As has beenpointed out by investigators, what is known as the wire and sheathreturn, consisting of a wire surrounded by a coaxial tubular conductorinsulated therefrom, is only a special form oi' the Lecher system and issubject to the same laws as the simple system. The general theory hasshown that in this Lecher system of conductors, or for a wire and itssheath return, the self-induction and capacity are evenly distributedand are reciprocals per unit length oi' the systemthat is to say, thecapacity and self-induction cancel each other as far as the dimensionsot' the wire are concerned; that the period of vibration is independentof the distance between the two wires and of their diameters. Such asystem el conductors is known in the art as a distortionless circuit.The velocity of propagation thereon iowl 'f-urcquency oscillations isapproximately t. at ot' light. For example, this is t-he velocity whenthe resistance per unit length is negligible compared to theself-induction and when this self-induction is the reciprocal ot thecapacity per unit length. 'lhese conditions are satisfied when the wiresare less than one-half millimeter in diameter and less than l() meterslong.

The formula for the sel t'induetion per unit 0 where (l is the distancebetween the centers of the two parallel wires and 0^ their comin onradius. The expression Ylor the capacity per un it length is the exactreciprocal of the above,

length of the Lcchersystem is Lzllog. nat.

l or :S1-, hence the remarkable property of the Lecher system that thevelocity ol the propagation oli' an electric wave along its length isindependent ot' the size ot' the wires or of the distance between theircenters, and this velocity comes out as equal to the velocity of light.This being the case it will be at once understood how the period of anysection of a Lecher system embraced between two consecutive bridges is afunction ot' the length between said bridges alone. Allencc inarrangements shown in Figs. 20, 2l, 22, and 24 the velocity oitpropagation along section B B is identical with that along section B2B3, and if the length oi' these two sections is the same the period ofoscillation of each section will be the same; but although the product(L S) be the same for both, L is small in B B and large in B2 B3, whileS is large in B B and small in B2 B3. Now the relative quantities ofelectromagnetic and electrostatic energies depend wholly on the ratiooi' L to S. XVhere self-induction is large and capacity small, wewillhave a greater proportion of the total energy as energy of inertiaor momentum. l/Vhere capacity is large and selfinduction small, we willhave a greater proportion of the total energy as energy of elasticity.Hence in passin from B B' to the section B2 B3 we will have atransference oli' energy 'from the electrostatic to electromagnetic forexample, two opposite charges are traversingB and B. \Vl1en these passupon B2 and B3, respectively, where the capacity is less,their potentialdifference must be increased, and vice versa.

On account of losses from resistance, leakage, and imperfect reflectionat bridges or open ends in such a system ol parallel wires as is heredescribed the stationary waves set up therein are never perfect, andtherefore absolute nodes are never found in practice, although withsuitable refiecting devices the approximation thereto when aslowly-damped wave-train is transmitted is very goed. lVe get insteadpoints oi' maximum and minimum potential difference and oi' current,whose magnitudes are dependent on the coefficient of resistance,leakage, and reflection.

Ordinarily the order of magnitude ol' the energy involved in the twosets of waves (the electrostatic and electromagnetic) is the same, andif the parallel wires were inlinitely small in diameter the 'magneticforce must equal the electric, and the greater the surface the lessbecomes the magnetic i'orce relative to the electric, the one increasingas the other decreases.

The characteristics and advantages of the Lecher system are:

(u) It is to a high degree a resonant vibrator-that is, it has a verymarked periodof its own and is very little responsive to oscillations olany other frequency than its own.

(l1) It is a poor radiator, and consequently a persistent vibrator,persisting for some time in its vibrations once they are set up,therefore producing a long wave-train and damping slowly. This isbecause most ol' the lines of force lie in the space between the two eonductors,and the radiation losses are therefore small, except when aradiator is attached.

ymay be readily predetermined.

One authority states that the observable `magnetic effect from-a Lechersystem, even .strongly excited', does not extend beyond threecentimeters from the parallel wires.

(c) By reason of the stationary waves set up higher potentials areobtained than are otherwise possible.

(d) The nodes and loopsv of these stationary waves are fixedly located,thus enabling connections to be made with the wires at any phase of thewave desired.

' (e) The system may be easily and accurately timed to anyfrequencydesired.

(f) Itis simple in its mathematical and theoretical aspects. Itsconstants are easily calculated and regulated, so that the dimensions ofa system for securing definite results This has not yet beensatisfactorily done for other forms lof apparatus employed in connectionwith,

currents of very high frequency, such as are employed forspace-signaling. The velocity .of transmission in a simple Lecher system`is approximately equal to Vthat of light. Therefore the wave lengths orfrequency may be readily determined and exactly defined. A briefdescription of the phenomena and laws vobtaining in such a system ofparallel conductors has been given by me in the Americcm Journal ofScience for July, 1899.

I have discovered lthat these characteristic features of the Lechersystem of wires render them especially adaptable for use in wirelesstelegraphy. In their application theyare exible, being adaptable tovarious modifications as may be required by the various circumstances,as the type of transmitter or receiver employed and the practicabledimensions of the apparatus, as the height and character of the uprightwire.

In the figures of the drawings accompanying herewith I have shownvarious modifications in which the Lecher-wires are employed, somerepresentingthe sending'apparatus and others the receiving` apparatus,althon gh in general either a sending or a receiving apparatus may beemployed with either.

In Fig. 2 I have shown Lecher wires B B in use with a receiver, onewire, B, connected with an 'upright wire or antenna-A'and the other, B',connected with the groundG or` other capacity. The Vequivalent length ofthe upright wire or collector AA is one-quarter of the wave length ofthe natural oscillation to which the system is attuned. At a distance ofone-half Wave length from the foot of the upright, as at 1, occurs thefirst node, andif the wires are long enough other nodes are formedseparated by the same distance as the node 2 shown in the figure. AtVthese nodes the wiresmay be connected Aby no-resistance bridges, as CC, without destroying or seriously affecting the oscillationsor thepropagation of the waves. These bridges may also be grounded, as -shownbydotted lines at AGrv in Fig. period of vibration. Y

static.

4, withouty affecting theA If the wires be continued one-quarter wavelength-beyond the last node, as shown in Fig.

2, a loop of electrostatic force will be formed' by the openendreflection. At such open ends all the energy of the system is electro-Therefore, as the sensitive device operated by a difference of potentialacross its terminals, such as a coherer or other responder,maybeinsertedmost advantageously ata static loop, these ends form a desirablelocation for such a device. kThe dotted lines D, Figs. 2 and 3,indicatethe position and intensity of such waves in the system. In Fig. 2 aresponder is shown at R as inserted between the open ends of the Lecherwires.

Such a device may, however, be inserted wherever an electrostatic loopoccurs. A sensitive device operated by current or electromagneticstationary wave, such as a bolometer or thermo element, should be placedat the loop of an electromagnetic wave. tromagnetic waves do notcoincide in location with the electrostatic waves, but, as is well knownin the art, are separated along the wire by ninety degrees or `by aquarterwave length. The relative positions of these different waves areshown in Fig. 3, in which the dotted line D represents the electrostaticwave, and D the electromagnetic wave. A

The elecbolometer or other device operated by current or electromagneticwaves may be located at any loop of an electromagnetic wave. Such adevice is shown at R/ in Fig. 3.

Since the simple antenna A is a stronglydamped vibrator and the systemof parallel wires attached at its base a weakly-damped orstrongly-resonant vibrator, it sometimes results that a violentoscillation received by the antenna, if strongly damped, may excite inthe parallel conductors vibrations having the distinctive period of saidconductors, re-l gardless of the period of the exciting impulse.

lWere this exciting impulse, however, a long wave-train, interferencesin the parallel wires would arise and they effect above described couldnot obtain; Conversely, if this long wave-train have the frequency towhich the wire systemvis attuned this latterwould beviolently excited.Thus by regulating@ the sen- IOS IIO

sitiveness of the receiving device Rresponse to oscillations other thanthose to whichthe system is attuned may be-prevented.

In Fig. et the Wire and sheath returnis shown,

wherein, as in the Lecher wires, the self-induction and capacity arealso evenly distributed. This, as shown, consists vof a centralconductor,A asa wire B', and an outer tubular conductor B surroundingit. These twoconductors may be connectedat thelocationY of electrostaticnodes by bridges, as C. As shown in Fig. 4, the waves travel uponthelouter surface of the inner conductor and back on the inner surface ofthe tubular or outer conductor: 4 The connections, however, oftheantenna and the ground-may befreversed, or we may regard the Iannularspace between` the :two conductors as the region within which-theetheric vibrations are confined. A responder, coherer, or otherequivalent device is shown as located at R, the same being at anelectrostatic loop.

In Fig. 5 the wires B and B are simple Lecher wires, such as describedin connection with Fig. 2. The antenna A of Fig. 2 is, however, replacedbythe conductive cylinder A, connected with wire B and the central wireA2, which latter is connected with the wire IB. These form a wire andsheath return system employed as a radiating' or a receiving antenna.This is only an exemplication of the wire and sheath return employed asan antenna. lVhen used as a radiating antenna and ground connection madeto the inner conductor, as Gr, the field of force is divided, part lyingbetween the exterior of conductor A and the ground and the greaterportion concentrated in the annular space between the coaxial conductorsAand A2. This arrangement results in a conservation of force, only asmall portion of the energy being radiated outward at each oscillation,but these oscilla` tions are continued for a considerable time. lVhenused as a receiver, the sensitive device, if of the type of theresponder, should be located at a static loop, as shown at R.

In Fig. G the conductors B B are the simple Lecher conductors, one et'them beingl connected with the ground G. The simple antenna is replacedby two plates A3 and A4, which may be considered simply as an extensionof the Lecher conductors. Il the planes of these two plates be paralleland adjacent, the greater part of the energy is concentrated iu thefield therebetween. The region lying in front of A'1 will at one instantbe occupied by lines efforce representing, say, a positivewave, and thatbehind AS will at the same instant be occupied by lines of forcerepresenting a negative wave. The respective lines of force radiatingfrom these plates are constantly changing their sign, oscillating fromone to the other, but are always of opposite sign in the respectiveregions and at points the same number oi' wave lengths distant fromtheir respective plates. In the region of the plane parallel with theseplates the radiation will be comparatively small and consist equally ofradiations from both plates. The waves in this region will thusneutralize each other, and a receiver located in such region will belittle affected. From the fact that one plate, as A4, is grounded itresults that the waves received thereby are dissipated to earth direct,thus preventing that condenser action by which. the intensity of itscharge is built up and lines of force established between the plate andthe earth. The plate Al being connected with the earth there is nodiilerence of potential between this plate and the earth, and thereforeno connecting lines ot' force. For these reasons radiations therelromare comparatively slight. The region of strongest propagation istherefore outward from A, and, as the plate Al tends to absorb the linesof force which proceed in its approximate direction, the direction oi'stron gest propagation is perpendicular to its plane. This featureenables the direction of propagation of the effective energizing orsignaling waves to be in a measure controlled or directed or, in otherwords, provides for the maintenance oi' a neutral zone or zones. Il'these plates be mounted so as to be rotatable upon a common axis, theposition of these neutral zones may be controlled, and the sameapparatus may thus be utilized for signaling in any direction desired,while approximately non-effective in other directions. This fact mayalso be utilized in preventing interference between different apparatuslocated in a common field of energy which would otherwise interfere witheach other. lVhen used as a receiving antenna, the rotative plates maybe utilized for receiving messages comin g from a given direction, whilein considerable measure neutralizing or cutting out the waves comingfrom other' directions. It follows that if the device has a direction ofmaximum propagation and directions oil minimum or no propagation it willconverselyhave directions of maximum and minimum sensitiveness to thereception ot' waves, from which it follows that if more than one seriesol waves are coming in it will be most responsive to those which comefrom its direction of maximum eliiciency, and also by turning` theplates to the position where the message is most clearly received theplate A3 will be .found to be facing the direction from which theimpulses are received. ln this way the direction `from which a signalcomes may be approximately told.

It' it is desired that both antenna be charged alike instead ofoppositely, as may at times be desirable to secure increased radiatingor collecting` power, this result may be obtained by inserting' betweenthe base ol one and the leg of the Lccher system connected thereto aretarding device, such as a coil or length of wire equivalent in lengthto one-half wave length of the oscillation for which the system isattuned. Such a coil is shown at E in Fig. 7. It used as a receiver, awave traveling down the antenna Ai will be delayed by its passagethrough the coil E by a time equal to one-half its period, and so will.enter upon its arm of the Lecher wires at a time when a wave of oppositesign enters upon. the other arm of the Lecher system. Thus the necessarycondition ot waves of opposite sign in the Lecher system is fulfilled.

In Figs. 8, 9, l0, and ll means are shown for exciting my apparatus orfor transmitting thereto the electrical oscillations necessary whenemployed as a sender. These figures do not show all the means whichmaybe employed for this purpose, but are given as illustrative ofwellknown means which adapt themselves to this use.

In Fig. S a static .method el charging is shown. The parallel or Locherwires are shown as of only one-half wave length. In.- serted in thebridge across their ends is a con- ICO IIO

denser K. In shunt around vthis condenser are a spark-gap S and thesecondary coil T of a transformer T T. 1When this'condenser is chargedto. the breaking-down point of the spark-gap S, a discharge occurs atthis point,

and this serves as a connecting -bridge between the parallel Wires, andthese Wires are set in vibration as a Lecher system. Part of the energyis reflected back at O and O', forming stationary waves with nod es at Oand O'. A part goes into the upright conductor or antenna A and isradiated outward.

In Figs. 9, l0, and Il the Lecher system is charged inductiVely-that is,the secondary 'l" of the transformer is in the circuit of the Lechersystem and oscillates therewith, while in Fig. 8 it is not in suchcircuit and does not enter directly in its oscillations. In fact, inFig. S the transformer may be replaced by any source of electricalenergy giving the requisite potential.

In Fig. 9 the parallel Wires are shown as equal to one-quarter Wavelength, and the coil T', forming the secondary of the transformer, isequivalent to one-half wave length. The primary coil T of thistransformer is connected in series with condensers K and sparkgap S.This primary system is charged from any suitable source of energy I. Itis necessary that the self-induction of the primary coil T and thecapacities K be so chosen that the natural period of oscillation of thisprimary system is equal to that of the adjoining Lecher system.

Fig. 10 shows a system essentially the same as that shown inFig. 9,except that a condenser K is connectedto the Lecher'wires at the staticloop. A condenser so located is the equivalent of a certain length ofparallel Wires, so that a system containing the condenser vibrates witha period of one having longer Wires or reduces the length of wirenecessary for a system of a given period. The effective capacity of sucha condenser depends somewhat upon its location in the stationary wave,it being most-effective when llocated at a static loop-viz., at a pointwhere the potential diiferenceacross its terminals is maximum.

It has been observed that a capacity orcondenser located across the twoLecher conductors exerts a greater or less distorting or absorbingeffect upon the wave system, according as it be located near anelectrostatic loop or near a node. If near aloop,-tl1e potentialdifference across its terminals is greater. Hence the quantity ofelectricity capable of being stored thereby is correspondingly greater,and the effect of this storing up at such a point is proportional,therefore,

to the location of the condenser in the Lecher system. In other words,While the absolute capacity is independent of this location itseffective or equivalent capacity is dependent thereon.

The use of a condenser as a means for adjusting the period or equivalentlength of a 'armatures of the condenser behavev as the system, for whichpurpose it is most effectively placed adjacent a static loop, should be.distinguished from its use in a bridge to pre- 7o Vent direct connectionbetween the Wires, as is shown at K in Figs. l, 17, and'25, Where it islocated at a static node. In this position it acts as a bridge, while atthe same time insuring the transfer to the system beyond the bridge of alarger percentage of the energy than Wo uld a plain wire bridge ordirect connection. It is, however, not altogether devoid of an effect inlengthening the 'period ofthe system. Condensers maybe employed 8o forboth of these purposes in the vsame system, as is shown in Figs. l and25. l Fig. 1l, shows the Lecher Wires cut at static loop and a condenserinserted in such cut between the Lecher wires and the -secondary 85terminals of the transformer. Here also the equivalent of a certainlength of Wire, this relation depending upon the amount of sur- Aface inthe condensers and the distance be- 9o tween the armatures, This affordsa ready means of attuning the system Vby changing -the distancev betweenthe armatures of the condensers. Since the maximum potential of oppositesign occurs at the terminals oftie secondary Tof the transformer, themiddle point of the coil must be one of zero potential and may thereforebe grounded,as shown at G, without interrupting the'acti on of thesystem.

-If the devices shown in Figs. lO or 11 are roo used as receivers, thetransformer-coils T and T should be reversed `in arrangement, as shownin Fig. l2, the low-potential coil T being connected with the Lecherwires, and the receiving instrument or responder R may be substitutedfor the spark-gap S. The same necessity arises in this case as in thesender 'for tuning alike the two circuits/shown.

In the receiver it is not always necessary to ground any point o-f theLecher system im of wires. In Fig. 13 if a node be formed, as at O, atthe base of the upright A stationary waves Will be set up in theparallel wires, as before, and in the absence of any earth connectionthe energy of the oscillations has no opportunity to leak away and mustbe con- Vsnmed only in heat and reflection losses in` the receiverinstruments. To insure the formation of a node at O, a large capacity,as K2, may be connected at this point. If a con- [z denser, as K, bevconnected at O between the two wires, its capacity should be small. A`condenser at this point in the system shown acts as a bridge.

In Fig. I4: is shown a method of reducing the actual length of wiresrequired to form the equivalent of the proper Wave length, whichconsists ininserting coils Ll L" in thev wires of the Lecher system.These coils should be'inserted at loops of c'urrent'where their inductlive or impedance effect willbe maximum.; If theLecher Wires are to bebridged, thes bridges should connect the middle points o'; itWocorresponding coils, as shown at C.` Q f In Fig. l I have shown a systemwhich employs both inductance coils L and a condenser K as lagproducingor period-adjusting devices. l also show a condenser K employed as abridge at the base of the antenna. The bridge C, which connects the twoinduet ance-coils, might be of the same form. '.lhe wave-producingdevice is of the same construction and is connected with the system inthe same manner as that shown in Figs. 9 and l0.

The use of bridges at the nodes of wires of more than one-half wavelength and placing the receiving instrument beyond saidI bridge orbridges has one advantage. The bridge, if grounded, will have the elfectof leading oft' or groundingwaves of such lcngtlrtliat their nodes areformed elsewhere and will thus screen or protect the responder orequivalent receiver from the effect of all waves except those which areof the length for which. the apparatus is adjusted. Upon waves of theproper length the bridges produce but little effect of this character.

It is not always necessary that the two parallel or Lecher wires be ofthe same length. Fig. l5 shows an arrangement in which the iesponder Ris located at a static loop of the wires and one-quarter wave lengthremoved from the base of the upright wire. At this point in the lowerwire we have a static loop formed by open-end reflection. The node at Omay be connected to earth or to a capac- 'ly K2.

In all the foregoing' ligures the upper end of the upright wire has beenconsidered as the location of the static loop, of which the node was atthe base one-quarter wave length below it. Ii a body having a largecapacity, as K3 in Fig. le', be located at the top of the upright wireor antenna, its capacity may be such as to produce reflection in thewaves oscillating in the upright conductor equivalent in sign to thereflection obtained at a bridge in the Lecher wire system. This meansthat a static node will be formed at this point with a loop at the lowerend. The earth connection then should be at a point along the parallelwires one-quarter wave length distant from the base of the upright wireor antenna, where the second node will be located. As the capacity Kmakes a static node at the top of the antenna where ordinarily is astatic loop, the location of the condenser K corresponds with a staticloop. The condenser K of Fig. l0 is also at a static loop. In both casesthe condenser represents or absorbs a certain amount of the wave lengthand is so located as to shorten the apparent wave length of the Lechersystem. The condenser K in Fig. l shortcns the length necessary in l B',and consequently also shortens the ylength necessary in A to still keepAin resoiaiice with the attached Lecher system. The

responder may be located, as shown, in shunt around the condenser.

In Fig.'l7 is shown a convenient forni of using the Lecher wires. Herethe two wires,

which are insulated, are twisted together,

were coiled upon a spool, with convolutions parallel and near together,interference by induction between adjacent convolutions would arise; butwhen closely twisted such adjacent convolutions of the coil il' not tooclose together will not interfere with one another. In any considerablelength of the convolution one wire will iirst lie adjacent to anothercarrying current of like sign and then to one carrying current ofopposite sign, so that for any considerable length of wire the inductiveeffects from the two wires in the convolutions adjoining will beneutralized. In practice I have successfully used such wires twistedwith a pitch equal to three turns to the inch wound upon a'spool aboutthree inches in diameter with successive turns scparated about an eighthof an inch. Their use is not, however, limited to even a nearapproximation to the above proportions, which are given only to showwhat has been found successful without any intention of limiting myselfthereto.

So far as I am aware such. a method ol embodying the Lecher wires and ofutilizing their advantages has never before been used. It retainspractically all the theoretical ad vantages of the straigl'it parallelwires embodied in a compact form, which makes the apparatus portable andpractical. lVherever in the accompanying drawings or ldescriptionstraight Lecher wires are shown or described, it is to be understoodthat the twisted pair, as above described,may be substituted, eithercoiled, as shown in Fig. IS, or disposed in any suitable wayforinstance, as in Fig. l5). Bridges, a condenser, er any other device suchas described in connectionv with the previousy features may be insertedas desired and are controlled in location and action by the sameprinciples as apply to the simple straight wires. In Fig. I7 a responderR, chokccoils M M, a battery N, and a telephone Q, or other indicatinginstrument are inserted in a local circuit after the manner common inwirelesstelegraph apparatus.

As shown in Fig. 17, the responder is placed across the open end of aloop and one-quarter wave length distant from the responder, andone-half wave length distant from the upright A is or may be placed abridge C. To avoid shunting the local circuit about the responder, whichwould occur if ano-resistance bridge or a metallic connection were used,a condenser K is placed in the bridge, which condenser i s of suiiicientcapacity to act as a no-resistance bridge for theI-Iertzianoscillation,while form- IOO Vro

rentm.` .n ,A

Vhen employed in thesending device, it

may be desirable for purposes of insulation to` immerse the 'entiresystem in oil.

In Figs. 20,21, and `22 are shown construc tions bywhi ch the potentialm-ay be simply and effectively transformed either to raise or lower it,as desired The principle therein 'illus-.-

trated may be employed eitherin the sender 'or the receiver, but is moreespecially recommended fonuse inthe receiver. k i 1, y

The general theoryshows that the"` mutual induction of the Lecher wiresdecreasesas the two parallel-wires are brought closer t0- gether,becoming` zero forthejwiresin actual contact, and that conversely the,capacity of the system is thus increased.v Consequently if one system ofsuch parallel wires, as BB', Fig.- 2.0, of length equivalent to one-halfwave length of the vibration ltransmitted be added to another system,asBZ'BS, of the saine period of electrical vibration, lbut, having its.two parallel wires farther apart, then this second system B2 B3`maytake up the impulse transmitted from the first system unaffectedas toits period of vibration, yet transformed to a wave of higherpotentiah'but ofcorrespond-l ingly-diminished magnetic energy orcurrent. On the same principle ,if the iirst-mentioned system-say ofone-half wave length-havev for the dielectric betweenV its two 4parallelwires a substance of higher specific inductive capacity thanrthatbetween the two parallel wires of the second system then the capacity ofthe first system per unit length is greaterthan that of the secondsystem. The electrical energy will therefore be transferred from thefirst to the second system, altered inits relative proportions ofelectrostatic and electromagnetic energies. So -in the arrangement lastdescribed the transformation will be, as before, to step up thepotential and to diminish the currents flowing in the second system.Such a system is illustrated inFig. 2l, in which the wires B B areparallel throughout their length; but the first' half` wave length fromthe upright is inclosed -ina casing H, containing oil. Thus I employoneY pair of parallel wires-for example, lof length equivalent to ahalf-wave length of the vibrai tion transmitted-immersed in andseparated by an oil, and connected to one end of this system anothersystem of parallelwires vof a length also equivalent to one #half wavelength, but equally separated by air or by a dielectric of smallspecific induction capacity, and thus obtain between the two wires ofthis second systema higher difference of potential than existedbetween'the wires of the iirst sys tem. Such immersion in a duid mayresult in a change in the wavelength required for a given period. InFig. 22 a combination of both plans is shown, the rst half-wave length BB' being immersed -in oil and also -having its wires closer togetherthan the secondhalftelegraphy.

Y effect is transmitted inductively'.

therefor.

Wave len gthxlz Bv?, which vareA separated only byair.v A. Y lhendesirable to still further increase the ,self-induction of one of` such;systems of parv allel wires as I have described, I may insert atcorresponding points in each of the two wires `inductive or momentumcoils of suitable impedance and construction, as shown at VL L,

Fig. 24. Similarly, to increase .the capacity` .ofthe other system Imayattach to. each of ther parallel wires thereof an armature of acondenser of suitable area, as show-nat K',

`Such combination of systems as Ihave here device entirely differingfrom transformercoils, ordinarily so called,a device novel and usefullin'firs application to the art of space- In allthe figures so farmentioned the an- .tenna is `shown as dir'ectl-y connected with whatmaybe called the vresonant-con ductors-that is, withtheparallel conductorswhich produce the stationary Waves. This is, however, not a necessity,as the resonant conductors and theantennamay contain devices inf circuittherewith whereby theA wave Such a constructionis shown in Y Figs. 23and 26,in which T T represent thetwo coils of a transformer orinduction-coil, one being in the circuit of the resonant conductors VBBv` and VIVthe described thus affords astep-up or step-down other in thecircuit of the antenna. v When applied to a receiving device, the coil Tisl the primary coilA and .Tj the, secondary. When applied to a sendingdevice, they would bere- ICO versediin-position orfunctiojn. This methodof connecting the parallel conductorsandthe antenna may be employedinthe `forms illus! trated in the -other figures.v As shown -in thesefigures, the conductors extending each way from the center oftheA coilT' to thefrst bridge C or the pC intwl1e1eY the firstnodefis formed areeach theiequ-ivalentfof a1halfwave length,^the condensersK, if employed,being taken. into consideration. The con:- denser may, however, be dispensedwithandv `its effect produced by, employing some other form' ofY lag-producing device, suchas imped ance-coils,after the mannerillustratedin s Fig. 14forthe'conductojrsj B B'glengthened to the properamount. The indirectj or\ -in with the parallel-or Lecher:conductors-'may IIO :ductive method of connecting the :antenna beemployed generallywithihedevicesshown.

.in the otheriiguresin lieu of thedirect-connecti'onshown therein.VVherever in, the description or claims one formofconnectionfisspecified, I am lto be understoodasstatingor claiming thc other form toYbe an equivalent In Fig. 25y the last ,system with which the:receiver-circuit is connected isinductivelyconnected with the othersystemsiafter the manner shown in .Fig. i l2.

In Figs. 25 and 2G condensers vK'are y shown as placed in and formingpart of the conductive systems after the manner shown in Figs. II andI2.

In Fig. 2G the antenna is directly connected i with the ground G andinduetively with the resonan t system by the coils T T, as described inconnection with Fig.

In the foregoing description I have endeavored to describe suchmodifications and variations in the apparatus which maybe employed aswill make clear the principles ot1 my invention without intending toshow all the modifications which are available or feasible. Othercombinations will suggest themselves to one familiar to the art.

I am not to be understood as limiting myself to the forms or exactcombinations of various elements shown, as I am aware of othermodilications and combina-tions,which might be employed. The furthermultiplication of the drawings seems, however, to be unnecessary, asthose given serve to clearlyset forth the principles of my invention.

The scope ot' my invention is to be determined by reference to theclaims terminating' this specification, in which the omission in anyclaim of any clement or the failure to include therein any qualificationof an element is to be understood as a distinct statement that suchelement or qualiication isnot essential to that particular combination.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent- I. In an apparatus for space telegraphy, incombination, an antenna and two parallel conductors adapted to actinductively upon each other, one ot' which is electrically connectedwith the antenna, said conductors being each equivalent to a multiple ofa quarter-wave length.

2. In an apparatus forspace telegraphy, in combination, a-n antenna anda plurality of parallel conductors cooperating therewith and adapted todevelop stationary electrical waves.

In an apparatus for space telegraliihy, the combination with an antennaof two conductors each equivalent in length to a multiple of aquarter-wave length and adapted to the production in cach other ofstationary electrical waves.

LI. In space telegraphy, in combination, par#l allel conductors ada-ptedto the production off stationary electrical waves, and an antennaconnected to one ot' the conductors whose natural period of vibrationcorresponds to that of the parallel conductors.

5. In space telegraphy, in combination, parallel conductors adapted tothe production in each other of stationary electrical waves, and anantenna connected at anode of said waves to one of the conductors andhaving a natural period of vibration corresponding to that of theparallel conductors.

U. In space telegraphy, in combination, plural conductors adapted forthe production ot' stationary electrical waves, bridges connecting saidconductors at points corresponding with the nodes ol" said waves, and anantenna connected with one of the conductors.

7. In space tclegraphy, incombination,plural conductors adapted I'or theproduction of stationary electrical waves, bridges connecting saidconductors at points corresponding with the nodes oi'l said waves,ground connections for said bridges and an antenna connected with oneoi' the conductors.

S. In space tclegraphy, in combination, a plurality oiinutually-inductive cont'luctors adapted for the production ofstationary electrical waves, an antenna connected to one of saidconductors and a receiver located at a loop of said stationary waves.

S). In space telegraphy, in combination, a plurality ofniutuallydnductive conductors adapted for the production oi' stationaryelectrical waves, an antenna connected to one ol said conductors at anode of said waves, and a receiver loca-ted at a loop oi? said waves.

l0. In wireless telegraphy, the combination with an antenna, of twoconductors of substantially uniform separation, on e of said con ductorsbeing connected with the antenna.

1l. In wireless telegraphy, the combination with an antenna of twoconductors oi' substantially uniform separation, one ot' said conductorsbeing connected with the antenna, and tuning or period-adjusting devicesconnected with said conductors.

l2. In space tclegraphy, in combination, an antenna, two conductorsadapted to the production of stationary waves, one of said conductorsbeing connected with the base ot the antenna and a condenser between thebase of the antenna and the other of said conductors.

18. In space telegraphy, in comljiination, an antenna, two parallelconductors connected at one end and having a condenser between theirother or open ends, and an antenna connected with the open end of oneconductor.

let. In space telegraphy, in combination, an antenna, two parallelconductors connected at one end andmpen at the other, and an antennaconnected to the open end ot' one conductor, the joint lengths of saidconductors being equivalent to a multiple of one-quarter of the wavelength for which the antenna is adapted.

15. In space telegraphy, in combination, an antenna, a conductorconsisting of a wire and sheath return having one end oi the sheathconnected with the antenna, and the correspending end of the wireconnected with. a capacity.

1G. In space telegraphy, in combination, an antenna, a conductorconsisting 0l' a wire and sheath return having an end of 011e of saidmembers connected with the antenna.

17. In space telegraphy, in combination, an antenna, a conductorconsisting of a wire and sheath return having one end ot one ot' saidIOO IXO

-Which conductors is members connected with the antenna, fsai d wireandsheath return being4 equivalent in length to a multiple of aquarter-wave length.

18. In spacel telegraphy, in combination, an antenna, a conductorconsisting ofV a wire and sheath return connected withV a capacity, saidwire andsheath return being equivalent in length to a multiple of aquarter-wave length.

19. In space telegraphy, the combination with parallel conductorsforming a resonant system, an antenna connected with one end of saidsystem, and means connected with the said conductors for the productiontherein of stationary electrical waves, of a capacity connection betweensaid conductors adapted to lengthen their period of vibration.

20. In space telegraphy, the -combination with parallel conductorsforming a resonant system, an antenna connected with one end of saidsystem, and means connected with the said conductors for theproductiontherein of stationary electrical waves,.of a capacityconnection thereto adapted to lengthen their period of vibration.

2l. In space telegraphy, the. combination with parallel conductorsforming a resonant system, an antenna connected with one .end of saidsystem, and means connected with the said conductors for the productiontherein of stationary electrical waves, of a capacity connection betweensaid conductors adjacent to a static loop of said waves.

22. In space telegraphy, the combination with an antenna and twoparallel conductors adapted to form a resonant system, one of whichconductors is conncctedwith the antenna, of condensers inserted betweensaid parallel conductors.

23. In space telegraphy, the combination with an antenna and twoparallel conductors adapted to forma resonant system, one of whichconductors is connected with the antenna, of condensers insertedbetween'said parallel conductors at points corresponding substantiallywith the loopsofthe electrostatic waves therein.

24. In space telegraphy, the combination with an antenna and twoparallel conductors adapted to form a resonant system, one of whichconductors is connected with the antenna, ofy lag-producingv devicesconnected with such parallel conductors.

25. In space telegraphy, the' combination with an antenna and twoparallel conductors adapted to Aform a resonant. system, one ofconnected with the antenna, of lagproducing devices connected with suchparallel conductors, and means for adjusting said devices to control theamount of'lag produced thereby. Y

26. In space telegraphy, theA combination with an antenna and twoparallel conductors adapted to form a resonant systennone of whichconductors is connected with the antenna, of condensersconnected withsaid con` ductors and having their poles adjustable toward and from eachother.

:2.7.- In space telegraphy, in combination an antenna,.parallelconductors connected therewith and adapted to theproduction ofstationary waves, and a condenser betweenthe ends of said conductors.

I28. In space telegraphy, in combination,an

antenna, a conductor connected therewith 30. In an apparatus for spacetelegraphy, I

in combination, an` antenna, two parallel and mutually-inductiveconductors one of which is electrically connected with the antenna,

vsaid conductors being each equivalent to a multiple of a quarter-wavelength,and awaveindicating device connecting said conductors at a pointequivalent to a multiple of a quarter-wave length distant from saidantenna.

3l. -In an apparatus for space telegraphy, in combination, an antenna, aplurality of parallel conductors cooperating therewith to developstationary electrical waves, and a wave-indicating device placed in thefieldof said waves substantially at a loop thereof.

32. AIn an apparatus for spacetelegraphy, the combination with anantenna, and two parallel conductors each equivalent in length to amultiple of a quarter-wave length. and

adapted to the production of stationary elec trical waves, and awave-indicating device connecting said conductors at a pointcorresponding substantially with loops of said 33. In space telegraphy,in combination,

plurality of conductors adapted for the production of stationaryelectrical waves, bridges connecting said conductors and locatedsubstantially at nodes of said waves, an antenna iro connected with oneof the conductors andv a plurality of conductors adapted for the pro-.A,Y

duction of stationary electrical waves, an antennaconnected with one ofthe conduc-V tors, bridges connecting said conductors and locatedsubstantially at nodes of said waves,

and a wave-indicating device connected-with said conductorssubstantially at a loop of said waves and beyond a bridge from theantenna.

35. In space telegraphy, in combination, an antenna, a conductorconsisting of awire and sheath return having the wire and sheathconnected onewith the antenna and the other with a capacity and awave-indicating device connected between the wire and sheath.

. 36. vIn space telegraphy, incombination, an antenna, a conductor conisting of a wire and sheath return, one ol' which is connected with theantenna and a wave-indicating device connected between the wire and itssheath.

37. In space telcgraphy, in combination,an antenna, a conductorconsisting ol' a wire and sheath return, one of which is connected withthe antenna and a wave-indicating device connected between the wire andits sheath, at a point corresponding substantially with the loop of thewaves in said conductor.

3S. In space telegraphy, in combination, an antenna, a conductorconsisting of a wire and sheath return, one of which is connected withthe antenna, said wire and sheath return being equivalent in length to amultiple of a quarter-wave length, and a wave-indicating deviceconnected between the wire and its sheath.

39. In space telegraphy, the combination with parallel conductors, meansconnected therewith for the production in said conductors of stationaryelectric waves, of a capacity connection between said wires adapted tolengthen th eir period of vibration, and a waveindicating` deviceconnected between said wires.

4:0. In space telegraphy, the combination with parallel conductors,means connected therewith for the production in said conductors ofstationary electrical waves, a capacity connection between said wiresadjacent the static loop of the waves in said conductors, and awave-indicating device connecting said conductors adjacent astatie loopof the waves therein.

lil. In space telegraphy, the combination with an antenna and twoparallel conductors which are connected at one end one with the antennaand the other with the earth or other capacity, and a wave-indicatingdevice connected between said conductors.

i2. In space telegraphy, the combination with an antenna and twoparallel conductors,

one of which is connected with the antenna, of condensers insertedbetween said parallel wires, and a wave-indicatin g device in shuntabout said condensers.

43. In space telegraphy, the combination with an antenna and twoparallel conductors which are connected at one end, one with the antennaand the other with the earth or large capacity, and a wave-indicatingdevice connected between said conductors at a point along the wiressubstantially corresponding to a loop of the wave with which it isdesigned to operate.

44. In space telegraphy, the combination with an antenna and twoparallel conductors, one of which is connected with the antenna, alag-producing device operative upon said eonductors,and awave-inc`licating device connected with such conductors.

45. In space tclegraphy, the combination with an antenna and twoparallel conductors, one of which is connected withV the antenna, oflag-producing devices operative upon said conductors, means foradjusting said devices to control the amount of lag produced thereby,and a wave-indicating device connected with said conductors.

4G. In space tclcglaphy, the combination with an antenna and twoparallel conductors, one of which is connected with the antenna, ofcondensers connected with said conductors and having their polesadjustable toward and from each other, and a wave-indicatin g deviceconnected with said conductors.

47. In space telegraphy, the combination with an antenna, two parallelconductors, one of which is connected with the antenna, of a condenserconnected between said con ductors substantially at an electrostaticloop of the waves therein, and a wave-indicating device connectedbetween said conductors substantially at a loop of the electrostaticwave therein.J Y

4S. In space telegraphy, an antenna, a conductor connected therewith andadapted to the production of stationary waves harmonizing in period withthose of the antenna, a wave-indicating device connected with theconductor, and connections with said conductor between thewave-indicating device and the antenna adapted to remove from theconductor such waves as are not in harmony with its designed period.

49. In a sending apparatus i'or space telegraphy, the combination with awave-produc ing device and an antenna, of a conductor connecting thewave-producing device and the antenna and equivalent in length to amultiple of a quarter-wave length, and a sec-A ond conductor parallelthereto and acting inductively to produce stationary electrical waves.

50. In a sending apparatus for space telegraphy, the combination with awave-produc= ing device and an antenna, of parallel con4 ductorsconnecting the wave-producing de= vice and the antenna and equivalent inlength to a multiple of a quarter-wave length, and bridges connectingsaid parallel conductors substantially at nodes of the waves producedtherein.

51. In a sending apparatus for space telegraphy, the combination with awave-producl ing device and an antenna, of parallel conductorsconnecting the wave-producing de' vice and the antenna and equivalentinlength to amultiple of a quartervave lengtlnbridges connecting saidparallel conductors substan-` tially at nodes of the waves produced, andground connections for said bridges.

'2. In space telegraphy, the combination with a wave-producing deviceand a radiate ing antenna, of a plurality of conductors connecting thewave-producing device and the antenna and the other acting inductivelytherewith to produce stationary electrical waves.

53. In space telegraphy7 the combination with a wave-producing deviceand a radiat- TIO ing antenna, of a plurality of parallel con- Intestimony whereof IA have hereunto afduetors each equivalent in lengthto a mulfixed my signature in the presence of two Wittiple of aquarter-Wave length, said condncnessesn r tors being adapted to theproduction of stat LEE DE FOREST. 5 tionary vibrations, one of saidconductors Witnesses:

connecting the wave-producing device and H. L.-REYNOLDS, the antenna. li ADOLPH FUCHS.

